1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * udbg interface to hvc_console.c
4 *
5 * (C) Copyright David Gibson, IBM Corporation 2008.
6 */
7
8#include <linux/console.h>
9#include <linux/delay.h>
10#include <linux/err.h>
11#include <linux/init.h>
12#include <linux/moduleparam.h>
13#include <linux/types.h>
14#include <linux/irq.h>
15
16#include <asm/udbg.h>
17
18#include "hvc_console.h"
19
20static struct hvc_struct *hvc_udbg_dev;
21
22static ssize_t hvc_udbg_put(uint32_t vtermno, const u8 *buf, size_t count)
23{
24	size_t i;
25
26	for (i = 0; i < count && udbg_putc; i++)
27		udbg_putc(buf[i]);
28
29	return i;
30}
31
32static ssize_t hvc_udbg_get(uint32_t vtermno, u8 *buf, size_t count)
33{
34	size_t i;
35	int c;
36
37	if (!udbg_getc_poll)
38		return 0;
39
40	for (i = 0; i < count; i++) {
41		if ((c = udbg_getc_poll()) == -1)
42			break;
43		buf[i] = c;
44	}
45
46	return i;
47}
48
49static const struct hv_ops hvc_udbg_ops = {
50	.get_chars = hvc_udbg_get,
51	.put_chars = hvc_udbg_put,
52};
53
54static int __init hvc_udbg_init(void)
55{
56	struct hvc_struct *hp;
57
58	if (!udbg_putc)
59		return -ENODEV;
60
61	BUG_ON(hvc_udbg_dev);
62
63	hp = hvc_alloc(0, 0, &hvc_udbg_ops, 16);
64	if (IS_ERR(hp))
65		return PTR_ERR(hp);
66
67	hvc_udbg_dev = hp;
68
69	return 0;
70}
71device_initcall(hvc_udbg_init);
72
73static int __init hvc_udbg_console_init(void)
74{
75	if (!udbg_putc)
76		return -ENODEV;
77
78	hvc_instantiate(0, 0, &hvc_udbg_ops);
79	add_preferred_console("hvc", 0, NULL);
80
81	return 0;
82}
83console_initcall(hvc_udbg_console_init);
84